BASIC RESEARCH GROUP CORE 007 ? TRANSGENIC MOUSE / ES CELL SHARED RESOURCE PROJECT SUMMARY/ABSTRACT Since 1993, the overarching goal of the Transgenic Mouse/ES Cell Shared Resource (TMESCSR) has been to facilitate the generation, use and storage of genetically altered mice by the Vanderbilt research community. The resource currently provides nine different classes of services on a fee-for-service basis. They are: 1) pronuclear DNA microinjection, 2) ES cell microinjection into blastocysts, 3) cryopreservation of genetically modified mouse lines and long-term storage, 4) gene targeting in mouse embryonic stem cells (mESCs), 5) recombinase-mediated cassette exchange (RMCE), 6) BAC recombineering, 7) Southern blot hybridization, 8) rederivation/assisted reproductive techniques, and 9) TALEN and CRISPR/Cas9-mediated gene modifications. Some of these services have been provided for many years whereas others, such as TALEN and CRISPR/Cas9-mediated gene modifications, were launched more recently. The wide variety of services and expertise provided has supported a large number of different basic and translational studies relevant to the mission of the Vanderbilt-Ingram Cancer Center (VICC). While efforts remain focused on the generation and storage of genetically altered mice, the TMESCSR has the capacity for expanding human fibroblasts and to derive induced pluripotent stem cells (iPSCs) should the demand arise. Moreover, it should be noted that the TMESCSR has adopted more of a ?full service? mentality in recognition of the fact that some users now desire the derivation of a new mouse model, but sometimes lack all of the necessary experience and skills required to assist in its derivation. The many services that are offered, combined with a longstanding relationship with many members of the VICC, position the TMESCSR to continue to serve the diverse needs of VICC and other Vanderbilt investigators. In this regard, the TMESCSR has worked closely with the VICC to launch the CRISPR/Cas9 service and already has made one knockout and one germline point mutation using this technology, with four more projects in the queue. This service is expected to continue to grow rapidly, as using CRISPRs can now make ?knock-in? mutations in multiple genes at one time in 4-5 weeks and for as little as $3,000. Likewise, novel genetic models can be generated to mechanistically dissect tumor suppressor genes in the same timeframe and cost. Currently the TMESCSR is working on projects aimed at making conditional gene deletions (?conditional knockouts?) using CRISPR/Cas9 to insert LoxP sites flanking exons. This process is expected to revolutionize cancer genetics, as tissue-specific gene deletion can be achieved for less than $5,000 in fewer than five weeks.